Anyone have experience with these bolt hangers???

MJMobes wrote: I still dont get your post about the paint- "The damage to the corrosion resistance you do with a bit of sanding is nothing compared to the damage painting does so carry on. "

As others have mentioned, the painted (or powder coated) layer can induce crevice corrosion, and promote other forms of localized corrosion. Powder coating seems to be worse, but painting can be an issue as well. In fact, the majority of the stainless steel hangers that have failed in Hawaii were powder coated. The bare stainless steel hangers last longer. The best thing you can do is to do nothing. Dont paint the hanger, dont sand it, just use it. ;)

Back in 2010;- ".... Additionally, the Metolius powder coated stainless steel hangers (Enviro Hangers), shouldn't be used in marine or wet environments due to the same moisture trapping issues." Metolious Climbing.
Since coating conceals any corrosion preventing even the simplest visual inspection it is a terrible idea anyway.

From the surface corrosion point of view (and that´s where the other forms normally start) stainless steel depends on the extremely rapid oxidisation of chromium to provide a protective barrier. Passivating uses an acid to remove the iron particles on the surface which make up ca 70% of the material which allows the chromium oxide to form a (more or less)complete barrier. Removing the iron leaves a slightly rough surface thus the matte finish. Sanding this surface merely exposes new iron to begin the corrosion.
With mechanical polishing the abrasive removes the softer iron on the surface and smears the chromium over the resulting pits leaving a smoother surface with better corrosion resistance and a shiny surface.
It is a slow and therefore expensive job!
Electro polishing is in effect the same as chrome plating and leaves the same finish as mechanical polishing though there are arguments in the metal finishing industry about which is actually better.

There are a couple of negatives with electro polishing apart from the visual, it is generally non-selective in that the whole thing is polished so for glue-ins the chances of the glue actually sticking are considerably reduced. Hand polishing you can at least decide on which bits to polish.For hangers this is of no interest naturally.
In the real world the problem with electro-polishing is that it defies the old saying "you can´t polish a turd" and some countries appear to specialise in producing incredibly shiny objects which corrode at an astounding rate.

The golden rule of preventing corrosion in stainless is keep it clean so put it out there where the rain washes it and design so there is no-where for gunge to build up.

what this probably stoned layman is getting is it has to do with moisture getting trapped. Its probably no big deal in a dry spot at all but paint/primer etc can make it corrode in a wet area like a sea cliff/waterfall zone.

I know that wooden boat builders dont use stainless bolts below the waterline for basically the same reason.

Locker wrote:"In order to get good adhesion of the coating it is nescessary to destroy the oxide coating with some kind of etch primer, thus removing the stainless steel´s protective barrier. Once the coating is damaged the crevice corrosion can begin. " Is this an issue only when the process pointed out above takes place? What about when blasting on a little bit of PRIMER paint? Zero etching. ??? And THANKS Jim T for taking the time to explain all of this! These types of threads are my personal favorites. ;-)

I´m not a painter! There again I´ve painted plenty of the stuff. Things like Rustoleum are etch primers with zinc phosphate or red lead as the protective pigment so who knows what the real effect is. And when you look at what´s in a typical primer then God only knows what it all does anyway.
Coloured hangers are unknown in Europe so we´ve never bothered to find a good solution apart from looking into plasma coating which has the advantage there isn´t anywhere for moisture to accumulate since it becomes part of the metal itself. Even this isn´t a wonder cure since the coaters only say it increases the corrosion resistance to that of stainless steel which didn´t help a lot.
Can´t you just use a waterproof marker of a suitable colour or not bother like us? We climbed a route a few years ago on a granite dome in Arizona, the bolts were virtually impossible to find and the only things that would see them 6 pitches up were a couple of scrawny cows who didn´t appear to have much in the way of aesthetic sensibilities.

Jim Titt wrote:We climbed a route a few years ago on a granite dome in Arizona, the bolts were virtually impossible to find and the only things that would see them 6 pitches up were a couple of scrawny cows who didn´t appear to have much in the way of aesthetic sensibilities.

300 series especially seems to naturally "haze" over time. On, I'd guess, most rock surfaces they're low profile enough. It's the shiny plated stuff that's visible from space...

Jim, opinion on 400 series? Same issue with painting? The polished hangers really shine with a near mirror finish.

I remember that Metolius came out with that info on their powder coated hangers, but, didn't see it on their website. Hmmm.

Great info, Jim...thanks!

Brian in SLC wrote: 300 series especially seems to naturally "haze" over time. On, I'd guess, most rock surfaces they're low profile enough. It's the shiny plated stuff that's visible from space... Jim, opinion on 400 series? Same issue with painting? The polished hangers really shine with a near mirror finish. I remember that Metolius came out with that info on their powder coated hangers, but, didn't see it on their website. Hmmm. Great info, Jim...thanks!

With limited exceptions, painting any type of stainless steel can induce corrosion. If you really want painted hangers in a wet environment you will have to look into higher grades: 904L, 317, 2205, 6%Mo 2205, titanium, ect. I am not too familiar with 400-series SS, although I suspect superferritic 400-series like SEACURE would work, although it might be too brittle.

Superferritic is going to be really expensive. Even 904L, titanium and 6% Mo SS is quite expensive. It is probably not worth it to increase your bolting cost by 3 - 5x just so you can paint the hanger.

A less optimal alternative is to use 316SS. The Petzl hanger is made from 316 stock:

Locker wrote:Is the damage caused by the painting isolated or does it somehow manage to work it's way in?

Work its way into what? The types of corrosion induced by trapping salts and other materials under a paint coating are very localized. Trapping salt under a poweder coat could result in intergranular stress corrosion cracking, leaving part of the hanger esentially cracked in half, and only 1/8" to the side of the crack the hanger might be completely unaffected. However, corrosion anywhere on the hanger will reduce the overall strength of it, so it does not matter that one section of the hanger is unaffected if another section is affected by corrosion. Serious corrosion anywhere on the hanger or bolt is a threat to the intergerty of the bolt system.


How long would it take a painted hanger before it became a safety issue, if in fact it could even become one?

Who knows? Somewhere between a few days and a lifetime. It depends mostly on the location where the hanger is installed. If you are placing hangers in the desert, painting them probably wont do jack to affect their lifespan. But if you are painting hangers next to the ocean, the paint could have a noticeable effect in a short period.

The problem occurs when harmful substances (such as chlorides) gets trapped under the paint or powder coated layer. If nothing ever gets trapped under the layer, painting the hanger dident matter. But if something does get trapped under there, then you have a problem. That is where rain can help. Frequent rain will help remove harmful residuals from the hanger. If the hanger never gets cleaned, then whatever gets stuck on the hanger might stay there forever, thus possibly accelerating corrosion depending on what exactly is on the hanger. However, rain has a harder time cleaning the hanger if there is a paint coating on it, thus coming back to the same issue, which is that the paint can trap deposits on the steel.

Of the hangers and bolts that have failed in Hawaii (304 powder coated hangers, 304 uncoated bolts), most of them were about 10 years old when they failed. However, if they failed at 10 years, that means they likely started suffering from critical corrosion problems in 3- 5 years, as corrosion is a progressive model in which the strength of the hanger will gradually reduce until failure (although not necessarily linearly).

The effect of painting stainless (like most things on forums) is greatly exaggerated. If you paint your hangers they are not going to fall apart and you are not going to die. By the time they corrode we will all be dead (of old age).
bssa.org.uk/topics.php?arti…

Jim, here's the ingredients for the Rustoleum Camo Spray we use here in CT to within 2 mi of long island sound.

Data

Brian wrote:The effect of painting stainless (like most things on forums) is greatly exaggerated. If you paint your hangers they are not going to fall apart and you are not going to die. By the time they corrode we will all be dead (of old age). bssa.org.uk/topics.php?arti…

Rubbish, 20kN has shedloads of examples and plenty of other people as well. We know how to paint stainless but keeping the coating undamaged is impossible in our application so the information on the link is useless.

The Phoenix wrote:Jim, here's the ingredients for the Rustoleum Camo Spray we use here in CT within 10 mi of long island sound.

That´s the overcoat, the primer is an etch primer. The overcoat contains iron hydroxide which in the stainless world causes what is called rouging and is related to the oxides formed on the boundary of welds which are always a corrosion hotspot. But since the iron hydroxide is embedded in a polymer I doubt it´s really a problem. I still wouldn´t use it though since it doesn´t avoid the stagnant water problem.

Jim Titt wrote: That´s the overcoat, the primer is an etch primer. The overcoat contains iron hydroxide which in the stainless world causes what is called rouging and is related to the oxides formed on the boundary of welds which are always a corrosion hotspot. But since the iron hydroxide is embedded in a polymer I doubt it´s really a problem. I still wouldn´t use it though since it doesn´t avoid the stagnant water problem.

So does that mean there's two parts to the spray paint? A primer and the ingredients I listed above? Or are you assuming some primer is used before this this spray paint? Here's the link to the data sheet, rustoleum.com/MSDS/ENGLISH/…, I don't see anything about any other ingredients or primers. But then again this is all new to me...

On a lighter note, I would have thought the Mineral Spirits and the Ti would have been a big + for the hangers... hahaha.

Jim Titt wrote: Rubbish, 20kN has shedloads of examples and plenty of other people as well. We know how to paint stainless but keeping the coating undamaged is impossible in our application so the information on the link is useless.

Who is 20kN? Examples of what? Examples of hangers breaking because they were painted? Bullshit. Show me a link to a documented case of a hanger failing because it was painted. Anything other than that is engineers musing on the hypothetical.

Jim Titt wrote: I still wouldn´t use it though since it doesn´t avoid the stagnant water problem.

Can you help me clarify this a bit? I live in the NorthEast and we camo stuff so it doesn't get chopped or cause issues in parks (eyesore).
Typically it rains often here in CT so things get wet but to date we've never really had to place a bolt in wet seepage area where we'd find prolonged wetness or stagnant water. I also notice this stuff really doesn't stick well at all to the stainless so while the bolt might be around for 20+ yrs the paint really only lasts a season or so I'm wondering really what the long term effects of having short term paint in non stagnant water area.

I'm thinking going forward a good rule for us in CT is, IF it's a wet cliff, waterstreak, or other commonly damp/wet area, do not camo SS. If its above tree line, in the sun in a typically dry area camo'ing may effect the long long term viability but likely won't to any dicernable degree.

Brian - I think Jim or someone quoted some stuff in Hawaii.

Brian wrote: Who is 20kN? Examples of what? Examples of hangers breaking because they were painted? Bullshit. Show me a link to a documented case of a hanger failing because it was painted. Anything other than that is engineers musing on the hypothetical.

Have you actually read the thread?

The Phoenix wrote: Can you help me clarify this a bit? I live in the NorthEast and we camo stuff so it doesn't get chopped or cause issues in parks (eyesore). Typically it rains often here in CT so things get wet but we've never used the stuff or placed bolts in wet seepage area where we'd find prolonged wetness or stagnant water. I also notice this stuff really doesn't stick well at all to the stainless so while the bolt might be around for 20+ yrs the paint really only lasts a season or so I'm wondering really what the long term effects of having short term paint in non stagnant water area. To be honest I'm thinking going forward a good rule for us is, IF it's a wet cliff, waterstreak, or other commonly damp/wet area, do not camo SS. If its above tree line, in the sun in a typically dry area camo'ing may effect the long long term viability but even then, the stuff wears off pretty quickly sooooo....

Stagnant water is what the water that seeps between the paint layer and the metal is called, not the water outside! It has a problem that the salts in it become more and more concentrated and the ph value drops, it´s stagnant so has no or little oxygen which prevents the chromium producing its protective oxide barrier and the corrosion can be extremely rapid.
Can´t help with whether to paint of not, it´s unheard of over here in Euroland anyway and I don´t recommend it since it can reduce the hangers lifespan and conceals any corrosion from later users. It´s my job to make the hanger as safe as possible and last as long as possible not to worry about them being chopped.

Jim Titt wrote: Stagnant water is what the water that seeps between the paint layer and the metal is called, not the water outside! It has a problem that the salts in it become more and more concentrated and the ph value drops, it´s stagnant so has no or little oxygen which prevents the chromium producing its protective oxide barrier and the corrosion can be extremely rapid. Can´t help with whether to paint of not, it´s unheard of over here in Euroland anyway and I don´t recommend it since it can reduce the hangers lifespan and conceals any corrosion from later users. It´s my job to make the hanger as safe as possible and last as long as possible not to worry about them being chopped.

thats exactly what my boatbuilder told me, they actually get more life out of hot dipped galvanized than SS, granted its encapsulated in the frame of the boat which is soaked in salt water for 6 months a year.

safeclimbing.org/education/…

seems like this find ought to be updated a bit

Locker wrote:20kn, Very interesting. Thanks! "Work its way into what?" The metal. "The problem occurs when harmful substances (such as chlorides) gets trapped under the paint or powder coated layer. If nothing ever gets trapped under the layer, painting the hanger dident matter. But if something does get trapped under there, then you have a problem" Hypothetical then: Home, relatively controlled environment (aka garage), SS hangers, PAINT (Which kind is best?). If I rinse, then air dry the hangers and paint, should be AOK? EDITED: Somehow I missed seeing this part: "It depends mostly on the location where the hanger is installed. If you are placing hangers in the desert, painting them probably wont do jack to affect their lifespan. But if you are painting hangers next to the ocean, the paint could have a noticeable effect in a short period." I think that answers my question nicely. THANKS AGAIN!

If you are bolting stuff in your garage, you dont need stainless period. Carbon steel is fine for a sheltered environment. And yes, you can paint them with whatever you want as they are not in a corrosive environment.

For the nonbelievers, here are some pics of powder coated hangers that failed from chloride-induced corrosion (likely stress cracking corrosion):



There corrosions in one pic. The shackle likely failed from SCC. The top right bolt possibly failed from crevice corrosion, the bottom right likely failed from pitting and possibly crevice corrosion or SCC.






Of the hangers that have failed in Hawaii, most of them were powder coated.

Exfoliation corrosion:




Unlike painting and powder coating, anodizing aluminum helps resist marine corrosion. It actually does a good job.... until the coating is scratched off.

Larry S wrote:I agree with Locker about the nut/bolt shaft crowding the clipping area with a wedge type bolt. It can prevent some motion of the biner more than usual.

Have had these hangers pin a biner. Seems they are a bit too tight.

Get what you pay for, smaller size=less material=less cost. Plus the MIC thing.